1. Field of the Invention
This invention relates to medical IV administration line connectors. More particularly, this invention relates to needleless injection ports for the safe infusion and/or aspiration of fluids in intravenous and blood administration therapy.
2. State of the Art
Intravenous therapy has a long history of use in supplying patients with pharmaceuticals, liquid nourishment, or blood products. Prior art FIGS. 1 through 4 show that the current or conventional way of introducing parenteral liquid solutions and/or blood and blood products into a patient is by the conventional gravity feeding system 10. The feeding system 10 includes a container 12 that is either a bottle or bag for the parenteral solution, a tube 14 extending from the bottle or bag and connected to a Y-injection site 16 (piggyback or secondary Y-injection site), and a tube 18 from the Y-injection site 16 to a needle or catheter 20 which is inserted into a vein in the arm 22 of the patient. The vein-access needle or catheter is taped to the patient with adhesive tape 24 so that the chance of a detachment and disconnect from the vein is minimized.
Supplemental intravenous therapy from a piggyback or secondary bottle or bag 26 is introduced through the Y-injection site 16 into the primary intravenous administration set 10. As seen best in FIG. 3, the Y-injection site 16 which is integrated into the primary intravenous administration set 10 consists of two tubular conduits 16a, 16b which merge into a third tubular conduit 16c. The tubing 12 from the bottle or bag of parenteral solution of the primary intravenous administration set 10 is attached into the inlet port 16a of the Y-injection site. In similar fashion, the tube 18 is attached into the exit port 16c of the Y-injection site. A sealed entry port segment 17 of the Y-injection site 16 is provided by the extension conduit 16b which has a standard self-sealing latex rubber septum 17a at its inlet port to seal this port from leakage. Consequently, it is difficult for pathogens to enter the Y-injection site 16 via the septum port 17 because of the seal 17a. This self-sealing septum 17a is of a conventional design and includes coaxial annular aprons which fit over the conduit wall and grip the external and internal wall surfaces to hold the septum securely to the conduit 16b. Typically, a plastic shrink-band (not shown) is shrunk on the outer wall of the septum 17a to securely connect it to the extension conduit 16b.
The supplemental intravenous solution is introduced into the primary intravenous administration set 10 through the Y-injection site 16 by way of a primed-piggyback or secondary intravenous set 26. The piggyback or secondary intravenous set 26 has a hollow-bore needle 28 attached to its distal end, which in turn is inserted through the self-sealing septum 17a of the Y-injection site 16 and into the extension conduit 16b. This needle 28 is connected to a tube 30 which is connected to a drip-chamber (not shown) of the piggyback or secondary intravenous set 26. A roller clamp 14a, 30a is typically used on both the primary and piggyback/secondary intravenous sets to control liquid flow rates into the patient.
There are several problems associated with the standard techniques employed for intravenous therapy. If the piggyback needle 28 is not securely taped to the Y-injection site 16 and the primary intravenous administration set tubing 12, 18, patients can move their arms, or roll over in bed accidentally pulling the needle 28 completely out of the septum 17a on the Y-injection site 16. If this occurs, the self-sealing latex septum 17a will close off automatically and not allow liquid or contamination to enter the primary intravenous administration set 10. The primary intravenous solution in the bottle or bag 12 will continue to flow into the patient, but, the necessary supplemental pharmaceutical solution from the piggyback or secondary bottle or bag 26 will no longer flow into the patient via the Y-injection site 16. The consequences to the patient for this situation can lead to serious complications and even death if the condition is not noticed by a clinician immediately. Even if the clinician notices the detachment of the needle 28 from the Y-injection site septum 17a immediately, the needle 28 is now contaminated with pathogens and should never be introduced back into the septum 17a. A new sterile, piggyback/secondary intravenous set must be opened, primed, and a new hollow-bore needle reinserted back into the septum on the Y-injection site. Additionally, whether the needle 28 is accidentally detached, or, the clinician removes the needle 28 from the Y-injection site septum once the supplemental pharmaceutical therapy is completed for the patient, the exposed needle 28 is contaminated with pathogens and must be safely disposed by the clinicians without accidentally sticking themselves.
To avoid accidental removal, the needle of the piggyback or secondary intravenous set may be taped to the Y-injection site and extension port. When this occurs, the needle may be secured from detachment, but the needle cannot be easily and safely removed by the clinician when the supplemental pharmaceutical therapy is completed, thereby creating a higher incidence for an accidental needle stick injury. Also, because clinicians hold the Y-injection site with one hand while the other hand is used to insert the needle into the-Y-injection site septum, the clinicians may accidentally stick the needle directly into their hands holding the Y-injection site, or stick the needle completely through the Y-injection site wall into their hands.
The above description and problems associated with conventional continuous and supplemental intravenous therapy through a Y-injection site is similar to the problems associated with intermittent intravenous therapy using a "Heparin Lock" injection port 40 (FIGS. 2 and 4). A heparin lock injection port 40 is either connected directly to the vein-access device 20, or attached to a short catheter extension tubing set 42 typically with microbore tubing which is attached to the vein-access device as shown in FIG. 2. The heparin lock has a self-sealing septum port 44 which is similar to the septum port 17 described above. A conventional intermittent intravenous therapy could utilize a short-term primary intravenous administration set 26 with a hollow-bore needle 28 attached to the distal end of a tube 30. The needle would be inserted to the self-sealing septum found on standard heparin lock injection port 40. Another means of introducing supplemental intermittent pharmaceuticals to a patient is to perform an intravenous push utilizing a syringe with a hollow-bore needle attached. The drug is pushed into the patient through the heparin lock injection port 40. Once dispensed, the syringe/contaminated needle is removed from the self-sealing septum 44 on the heparin lock injection port 40.
As set out above, the common medical techniques for delivering supplemental liquid fluids to the patient necessitates the use of a hollow-bore needle. The needle is either attached to a secondary intravenous set or a syringe, and is inserted through the self-sealing rubber stopper on the heparin lock injection port or the Y-injection port that is integrated into the primary intravenous administration set. Typically, the needle is secured to the injection port only with tape. The needle can detach from the injection port resulting in a serious or fatal interruption of the flow of the intravenous solutions to the patient. Moreover, the exposed needle can easily be contaminated by contact with non-sterile objects. Sound aseptic techniques must be practiced by the healthcare professional in order to ensure that the sterile needle does not become contaminated and cause a nosocomial infection to the patient.
Since the discovery of the HIV virus that causes AIDS in the mid-1980's, a major concern among healthcare workers practicing the standard methods of delivering intravenous therapy is accidental needle sticks with a contaminated needle. When a needle is removed from an injection port, it may be contaminated with the patient's blood. The contaminated needle must be carefully disposed in a sharps container. While handling the needle during removal and disposal, clinicians may, and often do, inadvertently stick themselves. Among all of the needled medical devices used in healthcare facilities, contaminated intravenous needles are responsible for the most accidental needlestick injuries. When a needlestick injury occurs, the clinician must stop work and have a blood test performed. Since a needlestick injury can result in fatal disease, the injured clinician will also experience tremendous emotional trauma.
There is a wealth of prior art concerned with the problem of accidental needlesticks. Needleless valves are known in the art of intravenous administration. For example, see my prior U.S. Pat. No. 5,395,348. In particular, with respect to "heparin lock"-type connectors, several design criteria have been determined for the satisfactory functioning of the connector. First, a fluid flow of at least 150 mL per minute at gravity is desirable. Second, it is desirable to limit the priming volume to not more than 0.05 mL. Third, it is desirable to provide with valve connector with as little dead space as possible. The amount of dead space is of great concern, especially when designing an injection port which will be coupled to an intravenous line. When a valve is closed, i.e., after the injection of a drug and removal of the syringe, the dead space can cause reflux; that is, a backflow of fluid into the valve which can draw an amount of blood equal to the volume of the dead space into the intravenous line. The blood can coagulate and obstruct the flow through the intravenous line, at least necessitating the use of a new intravenous line, and possibly causing severe detrimental effect to the patient. My U.S. Pat. No. 5,788,215, provides an injection port system which meets these requirements. The unit is non-swabbable; i.e., it has no exposed surface at the location of receiving an injection of a fluid into the valve and, as such, has good antiseptic properties.
However, health care professionals, through habit, prefer a system which is swabbable; that is, which has an exposed surface which can be cleansed (for example, with an alcohol-soaked cotton swab) prior to injection of a drug or parenteral solution therethrough. A consequence of providing an exposed swabbable surface is the increased susceptibility of bacterial buildup at or surrounding the surface barrier. It is difficult to contain the bacteria from penetrating the barrier.
Several prior art swabbable needleless injection port systems are known, but each has one or more disadvantages. For example, the Posiflow.TM. by CDC NIMA has a substantially low fluid flow rate (approximately 60 mL per minute) and significant fluid reflux (0.02 mL). In addition, while the unit is swabbable, the barrier is not satisfactorily microbial resistant. The UltraSite.TM. by Braun has a relatively large priming volume (0.35 mL). The SmartSite.TM. by Alaris has a relatively low fluid flow rate (approximately 120 mL) and a very large reflux (0.05 mL). The InterLink.TM. by Baxter has a very large priming volume (0.24 mL) and a large fluid reflux (0.04 mL). The ICU CLC2000.TM. has low reflux of fluid, but uses a piston-type valve which causes fluid to be forced out of the injection port around the luer connector. The difficulty in designing a needleless injection port connector which achieves all of the mechanical and antibacterial requirements is evidenced by the fact that several previously commercially available injection port systems have been recently removed from the market for unsatisfactory performance.